Exclaimer, 
I am not the one who made this amazing emulator, but I want to make it as clear as possible to be able to get half life on any device.

so far i have tested 

I HAVE TESTED - Xash3d (APK/IOS)
I HAVE TESTED - Webxash3d (WASM)
I HAVE NOT TESTED - xash3ds (for the 3DS)


Downloading half-life 1 on android / or using webxash if unblocked

first find the valve folder from the half life installation, 

  FOR - Xash3d 
once you have downloaded half life, copy/move the valve folder to xash3d from the half life folder. 
and it should be ready to go!

  FOR - WEBXASH3D 
pretty much the same as the other method, instead when opening webxash3d click the open game folder button, and search for the valve folder,
once you have found the valve folder select it. then it should show the valve files. models, media, events, maps, sounds, gfx, dlls, sprites, cl_dlls, and resource. if it shows all the files you should be ready to click start game.

  issues
- sometimes it will say "models folder not found" even though the model folder is in there, make sure you download the right version of half life, and have the correct folder - VALVE